Coriolis force

Coriolis force, apparent curvature of the path of a moving object due to the rotation of the earth. Because the earth rotates from west to east, any object moving in a straight line in any direction other than due east or due west appears to follow a curved path in relation to the earth's surface: to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This effect, named for the French physicist Gaspard Gustave de Coriolis (1792–1843), is most apparent in the movement of the winds and the sea. Allowances for this effect must also be made in ballistics in order to be able to calculate where a missile will land.